Trigger mounting for typewriter spool



Jan. 10, 1961 w. D. LANDGRAF ErAL 2,967,601

TRIGGER MOUNTING FOR TYPEWRITER SPOOL Filed July 14, 1959 INI/EMO@ Wurf-R D LANDGRAF R/cHA/w P LANDGRAF A TTORNEYS United States Patent O TRIGGER MOUNTING FOR TYPEWRITER SPOOL Walter D. Landgraf, 4808 96th Place, Oak Lawn, Ill.,

and Richard P. Landgraf, 9948 S. Hoyne Ave., Chicago, Ill.

Filed July 14, 1959, Ser. No. 827,098

1 Claim. (Cl. 197-175) The present invention relates generally to typewriter spools, and more particularly to typewriter spools having novel mounting and assembly devices for ribbon feed reversing triggers.

The typewriter spool of the present invention may be fabricated of plastic, and includes two parallel flanges, secured to a hub. The spool is designed to rest on one flange, hereinafter called the bottom flange, and a bent metallic trigger lever is provided, which is secured pivotally against the bottom ilange at the bend point thereof and includes an external arm extending below the bottom ange, and an internal arm extending generally axially of the hub, the pivot line lying approximately in the plane of the flange. The lever arms may make an angle of slightly less than 90 with respect to one another, and be so arranged that when the external arm is pressed against the ilange the internal arm lies fiat against the hub. When the internal arm is separated from the hub by rotation about the pivot, the external arm is separated from the flange, and in so separating performs its intended function as a ribbon feed reversing trigger.

The bent lever is secured to the bottom flange by means of a clamping plate, having clamping lugs extending through apertures in the bottom flange, and provided with downwardly depending ears having U-shaped openings for the saddling of the pivot points of the lever against the outer wall of the bottom ilange. In prior spools of the general type hereinabove described ears are provided with circular openings, and the ears must be bent over the ends of the pivot points to fasten the trigger in place. In accordance with the present invention, the ears are provided with U-shaped openings, the open ends of the Us facing the flange. The ears thus serve to saddle the pivot points against the flange. Thereby the lever may be assembled to the ilange without necessitating bending of the ears during assembly, which simpliiles and assures perfection of manufacture.

It is, accordingly, an object of the present invention to provide a novel mounting device for the reversing trigger of a typewriter spool.

It is another object of the present invention to provide a novel structure for securing the pivoted trigger lever of a typewriter spool to the ilange of a typewriter spool, wherein the structure possesses ears having U-shaped openings which open toward the ilange and saddle pivot points of the lever against the flange, eliminating any necessity for bending the ears over the pivot points in order to secure the trigger lever to the spool.

The above and still further objects, features and advantages of the present invention will become apparent upon consideration of the following detailed description of one specific embodiment thereof, especially when taken in conjunction with the accompanying drawings, wherein:

Figure 1 is a view in plan of a spool according to the invention, as seen from the underside;

Figure 2 is an enlarged view taken in section on the line 2-2 of Figure 1;

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Figure 3 is a view in plan of the spool of Figure 1, as viewed from above;

Figure 4 is a view of a trigger mounting plate, taken in perspective;

Figure 5 is an exploded view in perspective of the spool trigger and trigger mounting plate of Figures 1-4, inclusive, illustrating the mode of assembly; and

Figure 6 is a view in section taken on the line 6--6 of. Figure 1. f

Referring now more particularly to the accompanying drawings, the reference numerals 10, 11 denote two parallel generally circular ilanges, joined by a hub 12. The ilanges 10, 11 and the hub 12 may be one integral structure, fabricated of plastic, for example only.

The walls of the hub may include integral spokes 13a,Y

for strength, these extending to an inner boss 14. The hub 12 is provided with a llat 15, extending over an angle of about 20, centrally of which extends one arm 16 of a reversing trigger 17. The latter has the shape of a bent lever, including a second arm 18, which lies with its end 19 in contact with flange 10 on its outside when arm 16 lies parallel to the ilat 15. The trigger lever 17 is pivoted at its bend, on two oppositely extending pivot points 19, and the arms 16, 18 make an angle of slightly less than The trigger lever 17 is mounted on the flange 10 by means of a clamping plate 20, which is provided with lugs 21, which extend through suitable apertures 21a in the flange 10 and are bent under to secure the plate 20 to the flange 10. The plate 20 is generally circular but includes a radial extension 22 having a transverse window or opening 23. Two ears 24 protrude from the transverse ends of the window 23, and extend at right angles to the flange 10, outwardly thereof. The window 23 is aligned with a window 25 in the ilange 10, through which arm 16 extends.

The ears 24 each include a U-shaped opening, as 27, the openings extending into the radial extension 22, at 28. The U-shaped opening 27 serves to saddle pivot points 19 against the outer wall of flange 10, and the extensions 28 of the openings 27 serve to provide slots within which lie the pivot points 19.

In fabricating a typewriter ribbon spool according to the invention, the trigger lever 17 is placed in position, and the plate 20 positioned thereover. The lugs 21 then extend through the apertures 21a and are bent over to secure the plate 20 to the flange 10. This operation secures the trigger lever 17 in place, and provides bearings for its pivot points 19. It is then not necessary, as has been the case pursuant to the teaching of the prior art, to provide ears having bearing apertures and to strike up the ears 24 a-ter the plate 20 has been mounted so as to place the pivot points 19 within the apertures. This results not only in economies of manufacture, in that the operation is rapid and requires no skill, but has also been found to assure perfect alignment of the trigger lever 17 and freedom from spool breakage during fabrication. The ears 24 may be bent perfectly, in mass production, prior to assembly, and whereas the prior art procedure has proven diillcult and expensive and to lead to considerable spoilage, the procedure and construction of the present invention has effected a reduction of such spoilage t0 zero and ellected time economies in assembly.

By virtue of the utilization of a U-shaped opening 27 in ears 24, and the consequent utilization of the outer surface of flange 10 as a reference bearing point for the pivots 19, perfect alignment of trigger levers 17 is achieved automatically in all cases, without consequent time consuming adjustments, and without spoilage.

In operation, one end of a ribbon (not shown) is secured to a projection 30 lying diametrically opposite the lever arm 16, the ribbon then proceeding under the arm 1'6`fr one 'turnan'd 'thereafter over the arm 16. In consequence, when the end /of the ribbon is attained, during operation of the typewriter, the ribbon allows arm 16 to f all radially outward, which in turn allows arm 18 to fall axially outward. This action reverses ribbon feed.

While a preferred embodiment of the invention has been illustrated in the accompanying drawings, and described hereinabove, in which is employed a metallic clamping plate 20, secured to the ange 10 by means of lugs 21, it is possible, within the scope of the invention as defined by the appended claim to utilize a clamping plate formed of plastic material, cemented to the flange 10, or in any other desired manner secured thereto.

While we have described and illustrated one specic embodiment of our invention, it will be clear that variations of the details of construction which are specifically illustrated and described may be resorted to without departing from the true spirit and scope of the invention as dened in the appended claim.

What we claim is:

A spool for a typewriter ribbon, including a hub and parallel anges extending from said hub perpendicularly of the axis of said hub, a mounting plate secured to the exterior wall of 'one of s'aid anges, said mounting plate including a window communicating with a further window in said one of said anges, adjacent the outer periphery of said hub, said mounting plate including parallel ears extending outwardly of said mounting plate at the ends of said tirst mentioned window, Asaid ears each including a U-shaped opening having its open end adjacent to and communicating with said outer wall of said one of said flanges, and a bent trigger lever having one arm extending through said windows and between said anges adjacent to said outer periphery of said hub and having another arm extending generally radially and adjacent said outer wall of said one of said anges, said bent trigger lever having oppositely extending pivot points saddled by said U-shaped openings and lying against said outer wall of said one of said anges.

References Cited in the rile of this patent UNITED STATES PATENTS 2,304,498 Hart Dec. 8, 1942 

